1. Technical Field
This disclosure relates to an image forming apparatus, and more specifically to an image forming apparatus including a sheet cutting device to cut a rolled sheet to a desired length.
2. Description of the Related Art
Image forming apparatuses are used as printers, facsimile machines, copiers, plotters, or multi-functional devices having two or more of the foregoing capabilities. As a conventional type of image forming apparatus, an image forming apparatus is known that feeds a long-size rolled sheet (hereinafter, rolled sheet) in a certain feed direction (hereinafter, sheet feed direction) to form an image on the rolled sheet. The image forming apparatus typically has a sheet cutting device to cut the rolled sheet to a desired length by moving a cutter in a direction perpendicular to the sheet feed direction (hereinafter, width direction).
Such a conventional sheet cutting device needs to return a cutter unit holding the cutter to an initial position (home position) in preparation for the next sheet cutting. At this time, if a forward path along which the cutter moves to cut the sheet is identical to a backward path along which the cutter moves to return to the home position, the cutter might contact an already-cut sheet on the backward path, thus hampering movement of the cutter unit (so-called “cut jam”) or causing other failure.
To prevent such a cut jam or other failure, for example, JP-2009-214200-A proposes an image forming apparatus including a sheet cutting device in which the backward path of the cutter formed with a pair of circular blades differs from the forward path of the cutter. Relative to the forward path, the backward path is arranged at a downstream side in the sheet feed direction in which the sheet is fed along a sheet feed path and at a position away from a leading edge of a subsequent divided sheet upstream from the cutter in the sheet feed direction.
However, in the image forming apparatus described in JP-2009-214200-A, the cutter unit and the carriage holding the recording head are arranged independently of each other and in tandem in the sheet feed direction, thus resulting in an increased width of the image forming apparatus in the sheet feed direction. As described above, in the image forming apparatus, the forward path of the cutter differs from the backward path, thus preventing the cutter from contacting the subsequent divided sheet on the backward path. However, the cutter unit still remains on the sheet feed path after cutting operation. As a result, the subsequent sheet cannot be fed from the rolled sheet until the cutter and the cutter unit return to the home position, thus hampering gains in productivity.
Hence, in JP-2010-268563 (JP-2012-115952-A), the applicant of the present application proposed a sheet cutting device capable of dealing with such a challenge and an image forming apparatus including the sheet cutting device. In the image forming apparatus, the carriage is arranged to overlap the cutter unit in a thickness direction of a rolled sheet to reduce the width of an apparatus body in the sheet feed direction. Additionally, relative to the forward path, the backward path is arranged so as to be retracted from the sheet feed path in the thickness direction of the rolled sheet. Thus, after the cutting of the rolled sheet, the cutter unit is movable along the backward path with the cutter unit retracted from the sheet feed path.
However, in the image forming apparatus having such a configuration, because the carriage is arranged to overlap the cutter unit in the thickness direction of the sheet, a movement area of the carriage in the sheet width direction (the main scanning direction) overlaps a movement area of the cutter unit along the forward path. As a result, if the cutter unit moves when the carriage is placed on the movement area or the carriage moves when the cutter unit is placed on the movement area, the carriage and the cutter unit would interfere with each other.
For the image forming apparatus, for example, when the cutter unit and/or the carriage are not placed at the corresponding home positions, initial operation is performed to return (move) the cutter unit and the carriage to the respective home positions. For the initial operation, it is necessary to prevent the carriage and the cutter unit from contacting each other when the cutter unit and/or the carriage are/is returned to the home positions.